Diametrically Opposite Scaling of Extreme Precipitation and Streamflow to Temperature in South and Central Asia

Clausius-Clapeyron (CC) equation suggests a 6-7% increase in extreme precipitation per degree rise in temperature. Scaling rates of extreme precipitation with temperature at different regions significantly deviate from the CC rate. We find that the daily extreme precipitation scaling is negative over sites in the warmer tropical region of South Asia, as opposed to positive scaling over the cooler subtropics. Daily precipitation scaling tends to break down and becomes negative above a temperature of 23-24 degrees C in all the regions. However, such breakdown disappears for subdaily precipitation extremes, and they continue to increase at high temperatures over both tropics and subtropics. This leads to high positive streamflow-temperature scaling over small catchments, in contrast to extreme precipitation scaling at a daily scale, which is partly negative. Our analysis highlights an increased threat due to flash flood in a warmer climate, which cannot be fully estimated with the analysis of daily precipitation extremes.